Is it Prime? vs Cool Penguin Clock
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Is it Prime?
Enter any number to instantly determine if it is a prime number or not. This straightforward utility provides a quick answer to your mathematical curiosity.
- Prime number identification
- Simple number input
- Instant yes/no results
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This application serves only one function - to satisfy your curiosity when you wonder whether a given number is prime or not. You put in the number, it says yes or no. Really, that's all it does.
Cool Penguin Clock
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How about a cool penguin clock for the hot summer? You can choose from 20 different pictures of penguins. You can move the time text, analog clock, and penguin with your fingers. The analog clock and penguin can be zoomed in and out with two fingers. Seconds can also be displayed. Background color can be selected from 5 different colors. The year, month, day of the week, a.m./p.m., and seconds can be erased by touching them. Touching the time character switches to setting mode. When in setting mode, touch to change the year, month, and date to various formats. You can also switch between 12-hour and 24-hour displays. Screen rotation in portrait and landscape mode is also supported. By pressing buttons such as "2X" and "3X," the font size can be adjusted in steps. The time signal can be selected from 78 different tones.
Screenshots
Verdict
The clearest difference is in-app purchases: Is it Prime? at none against Cool Penguin Clock's 1. Is it Prime? also leads on ads (none vs shown). Cool Penguin Clock's advantage is update cadence (every 3 weeks vs every 74 months) and iOS requirement (12.0 vs 15.0). On price and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Cool Penguin Clock sells 1 one-off in-app purchase. Is it Prime? asks for nothing beyond the download.
Is it Prime? ships an update every 74 months, Cool Penguin Clock every 3 weeks. The most recent releases landed on October 11, 2026 and September 30, 2026 respectively.
| Parameter | Is it Prime? | Cool Penguin Clock |
|---|---|---|
| Price | Free | Free |
| Rating | 3.2 (5 ratings) — better | — |
| Positive reviews | 71.4% of reviews | — |
| Number of ratings | 5 — better | — |
| Update frequency | Every 74 months | Every 3 weeks — better |
| Ads | No — better | Yes |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 1 MB | 27 MB |
| Age rating | 4+ | 4+ |
| Developer | Wismar | Mihoko Araki |
In-app purchases
Is it Prime?
No in-app purchases
Cool Penguin Clock
- Penguin Clock with no ads$1.99
Questions
Is Is it Prime? free?
Is Cool Penguin Clock free?
Do Is it Prime? or Cool Penguin Clock have ads?
Which is updated more often, Is it Prime? or Cool Penguin Clock?
Other comparisons
